Froth flotation process



United States Patent 2,987,183 FROTH FLOTATION PROCESS William T. Bishop, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware 7 No Drawing. Filed Feb. 3, 1959, Ser. No. 790,812 4 Claims. (Cl. 209-166) This invention relates to a process of ore beneficiation and, more particularly, to a froth flotation process for concentrating nonmetallic and some metallic minerals.

In the flotation of minerals from ores to which this invention is applicable, i.e., Florida phosphate rock, barite, fluorspar, cement rock, iron ore, ilmenite and so on, it is standard practice to use anionic collecting agents to float the valuable mineral from the gangue. The collectors commonly used for this purpose are tall oil, tall oil fatty acids, petroleum sulfonates, red oil, oleic acid and similar fatty acids, soaps and analogous surface-active agents. Other flotation agents, such as frothers and modifying agents, may be used along with the collector to enhance its activity.

A principal object of the present invention is the provision of an eflicient and economic froth flotation process of the indicated type for recovering valuable minerals from ores.

Another and more specific object of the invention is the provision of a froth flotation process in which a new, efficient and low cost collecting agent is used to recover valuable minerals from ores.

The novel collecting agent employed in the process of the present invention is saponified tall oil pitch. Tall oil pitch is the residue or still bottoms resulting from the fractional distillation of crude tall oil whereby the fatty and resin acids and other distillable materials are removed leaving the pitch. It is a tarry, dark brown substance, the specific characteristics of which vary somewhat depending on the composition of the crude tall oil, the conditions of treatment and so on. The following is an analysis of a typical sample of tall oil pitch obtained by the fractional distillation of tall oil:

1 Free and esterified.

The process of the invention may be carried out using conventional procedures except for the inclusion of the novel collecting agent. In accordance with such procedures, the ore is first ground, usually in the presence of water, to the proper particle size for liberation of the mineral component from the gangue. The ground material is then screened to remove the oversized particles and the resultant pulp, in most cases, deslimed to remove the colloidal particles which are harmful to the separation by the flotation process. The deslimed pulp, at -75% solids, is then usually conditioned for a short time with the chemical reagents to be used, particularly the collector and the frother and, in some cases, modifying agents, following which flotation is carried out in any of the various types of machines commonly used for this purpose. customarily the valuable mineral is floated.

P ce However, the procedure may be reversed with the valuable mineral concentrated in the tailing.

The following examples will serve to illustrate the invention. In these examples the tall oil pitch used for the saponification was obtained by the fractional distillation of crude tall oil and had the following typical analysis:

Acid Number 40-60 Rosin acids percent 15-20 Fatty acids 7-12 Saponification number 115-125 Unsaponifiables 20-25 The saponification was carried out by reacting the tall Example 1 Six hundred fifty (650) grams of wet Florida phosphate rock of about 28% B.P.L. (tricalcium phosphate) was scrubbed for 2 minutes in a 500 gram Denver flotation machine. The scrubbed ore was mixed with fresh water which was decanted oif carrying with it the slimes. This operation was repeated twice to remove all the slimes. The deslimed sample was then conditioned at solids for 2 minutes with the following:

NaOH 0.19 1b./ton of original ore. No. 20 gravity fuel oil 1.38 lb./ton. Saponified tall oil plteh 0.81 lb./ton.

The conditioned ore was transferred to the flotation machine, diluted with water to about 25% solids, and the phosphate mineral floated ofi. A concentrate of 42.2% of the original weight was obtained which analyzed 61.9% B.P.L. (tricalcium phosphate). The tailing contained only 2.6% B.P.L., showing a good recovery of the mineral.

Example 2 Six hundred fifty (650) grams of a different wet phosphate rock of about 28% B.P.L. was scrubbed and deslimed as described in Example 1. The deslimed sample was conditioned at 70% solids for 2 minutes with the following reagents:

NaOH 0.19 lb./ton of ore; No. 20 gravity fuel oil 1.40 lhs./ton. saponified tall 011 pitch--- 0.72 1b./ton.

The conditioned ore was floated at about 25% solids which gave a concentrate of 37.4% by weight. It contained 15.7% hydrochloric acid insoluble material. The tailing analyzed 95.2% HCl insoluble showing that practically all the phosphate had been recovered in the flotation concentrate.

Example 3 Six hundred (600) grams of specular hematite iron ore was ground to minus 65 mesh in a ball mill in the presence of about the same amount of water. To the slurry was added 0.5 lb./ton of sodium silicate and the ore was deslimed by diluting with water and decanting. This was repeated twice to remove the slimes which amounted to about 10%. The deslimed ore was conditioned at 65- 70% solids for 5 minutes with the following reagents:

No. 2 fuel oil 1.2 lbs/ton. saponified tall oil pitch 0.70 1b.]ton,

Thus, a high grade iron-concentrate was obtained in good yield.

Example 4 In-this example acommercial carbonaceous rock flotation feed of 20% solidsw-as used. It contained about 6 7% CaCO Nine hundred (900) milliliters of this slurry was transferred to a 200 gram flotation cell and the reagents added to produce the individual floats as shown.

Per- Lb./ Per- Percent Reagents Ton cent cent OaCO;

Wt. CaC Recovery No. 2 fuel Oil 0. 09 Methyl Am yl'Alcohol 0. 14 Float 1-. 23.9 67. 23. l Sapomfied Tall 011 P1 0. 68' Tall Oil Fatty 0. 18 Float 2.- 33. 8 79. 6 38. 6 Sapom'fied Tall Oil Pitch" 0. 23 T811 Oil Fatty Acids 0. 09 Float 3 31. 0 75. 4 33. 5 Tail. 11.3 30. 2 4. 9

v The first ,floati-containedthe bulk of the carbonaceous material plus some ofjthe' calcium carbonateproduced by the saponified tall oil pitch plus asmall amount of the tall oil fatty acid.

In the preparation of the collecting agents utilized in the process of the present invention tall oil pitch is reacted with an alkali, i.e., the hydroxides or carbonates. of the. alkali metals. The reaction may be carried out at a temperature from about 1'001 C. .to about 200 C. and at a pressure from about 1 pound persquare'inch' to about 100 pounds' per square inch. The preferred c-onditions'of temperature and. pressure are from about 150 to;about 180f-C. and 'fromabout 30 to about 45 pounds per square inch pressure. The alkali is preferably added t0:.thezmolten1t'a1l oil pitch as an aqueous solution at a concentration from; about 20' to 50% depending on the solids content desired in the product. The amount of alkali may be varied butjshould be suificient to more than neutralize all the acidity of-the pitch. It is preferred to utilize an amount of alkali such that the final saponified' product contains from about 0.52.0% free alkali as NaOH. The saponified tall oil pitch,,prepared as described, is water-soluble or at least water-dispersibl'e. If desired, the paste product can be spray dried to give afree-flowing powdered material;

The objects of the invention are realized by employing saponifed tall oil pitch in amounts from about 0.1 to5 pounds per ton of ore, and preferably 0.3 to 1.0 pounds per ton in flotation processes for bcneficiation of ores. Injmost instances, it is advantageous to employ other flotation agents from the class of collectors, frothers,

and modifying agents along with the collector of this invention to achieve the most effective separation of the minerals from the ore. Typical collectors, frothers and modifying agents which may be used with the collectors of this invention are disclosed in U.S.P. 2,545,132.

The collector of this invention may be used generally in the flotation beneficiation of ores but is most advantageously employed on nonmetallic ores and oxide ores. For example, theflotation of barite, apatite, fluor ite, calcite, gypsum, spodumene, ilmenite, hematite, magnetite, chromite, magnesite and so on are some ofthe minerals which may be concentrated by the collector of this invention.

An important advantage of this invention is the conversion of a cheap raw material, with limiteduse in flotation and most difficult handling properties, into a watersoluble product of valuable collecting properties for a wide variety of minerals. While preferred embodiments of the invention have been exemplified, the invention is not intended to be limited to the specific details described except as they may be included in the following claims;

What I claim and desire to protect by Letters Patent l. The process of concentrating an ore selected from the group consisting of nonmetallic ores and oxide ores by froth flotation which comprises incorporatinga water-- dispersible s-aponified tall oil pitch prepared by reacting;

tall oil pitch with alkali at temperatures from about 15 0 C. to about 180 C. and at pressures from about 30 lbs./

sq. in. to about 45 lbs./sq. inein an aqueous ore pulp of.

the indicated type, agitating the pulp to form a froth, and separating the froth from the pulp.

2. The. processof concentrating an ore selected'from. the group consisting of nonmetallic ores and: oxide oresby froth flotation which comprises forming an aqueous ore pulp from such an ore, adding to said pulp from about 0.1 to 5 pounds per ton of ore of a saponified tall oil pitch prepared by reacting tall oil pitch with alkali at temperatures from about C. to about C. and at pressures from about 30 lbs/sq. in. to about 45 lbs./sq. in., agitating the pulp to form a froth, and separating the froth from the pulp.

3. The process of concentrating an ore selected from the group consisting of nonmetallic ores and oxide ores which comprises finely grinding such an ore and forming- References Cited in the file of this patent UNITED STATES PATENTS Breerwood Sept. 10, 1940 Gieseke Oct. 4, 1949 UNiT ED STATES" PATENT OFFICE CERTIFICATE OF CORRECTIQN Patent No. 2,98%183 7 June 6 19 1 William To Bishop It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as corrected below. I Y

Column 2, line 9, for "Rosin acids read em Free Rosin Ac ds (calculated as abietic acid) line 10 for Fatty acids" read Free Fatty Acids (calculated as oleic acid) column 3 line 155 after "caNoonaceous insert cementv Signed and sealed this 7th day of November 1961e (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents uscoMM-Dc 

1. THE PROCESS OF CONCENTRATING AN ORE SELECTED FROM THE GROUP CONSISTING OF NONMETALLIC ORES AND OXIDE ORES BY FROTH FLOTATION WHICH COMPRISES INCORPORATING A WATERDISPERSIBLE SAPONIFIED TALL OIL PITCH PREPARED BY REACTING TALL OIL PITCH WITH ALKALI AT TEMPERATURES FROM ABOUT 150* C. TO ABOUT 180*C. AND AT PRESSURES FROM ABOUT 30 LBS./ SQ. IN. TO ABOUT 45 LBS./SQ. IN. IN AN AQUEOUS ORE PULP OF THE INDICATED TYPE, AGITATING THE PULP TO FORM A FROTH, AND SEPARATING THE FROTH FROM THE PULP. 